
We haven’t had a 76ers-Celtics playoff series in 10 years, so there is a whole generation of NBA fans who may not understand the historical significance of their Eastern Conference semifinal showdown: They once hated each other. This is the 19th playoff meeting between Boston and Philadelphia and should be just an intense as all of the previous matchups. The fourth-seeded Celtics appear to have an edge in experience over the eighth-seeded Sixers. But there is a fine line between